HCC Insurance Holdings is a specialty insurance group operating across the U.S., the United Kingdom, Ireland and Spain.

Fortune 500 rank: 844 | Stock price (NYSE): $77.20

(Pictured: Tsuyoshi Nagano, president of Tokio Marine Holdings Inc., speaks to the media after a news conference in Tokyo, Japan, on Wednesday, June 10, 2015. Tokio Marine agreed to buy HCC Insurance Holdings Inc. for about $7.5 billion in the biggest acquisition by a Japanese insurer. Credit: Akio Kon/Bloomberg)

Rosetta Resources is an oil and gas exploration and production company. Another Houston-based oil company, Noble Energy, said last month that it would acquire Rosetta for $2.1 billion.
Stock price (NASDAQ): $19.98

Rosetta Resources is an oil and gas exploration and production company. Another Houston-based oil company, Noble Energy, said last month that it would acquire Rosetta for $2.1 billion. Stock price (NASDAQ):